The present invention relates to the fastening of a hydraulic control and positioning cylinder above the casing or housing in a stand and frame for a rolling mill, for the purposes of replacing a electromagnetic adjustment device by hydraulically operated one whereby the piston of the hydraulic drive is to penetrate that bore in the casing or housing that was used to accommodate an adjusting spindle, and wherein the free end of the piston rod acts on a mounting structure for roll, and wherein a structure is provided to take up the rolling force.
Generally speaking, it has become customary to modernize and refurnish older rolling mills and stand particularly because present day requirements concerning quality and concerning particular tolerances are no longer met by these older mills. In furtherance of this objective, the existing electromechanical roll adjustment devices and structures have been or are to be replaced by hydraulic adjusting devices. Alternatively, the existing electromagnetic roll adjustment is not replaced but supplemented in that one provides a tolerance improving supplemental hydraulic drive, basically constructed to have a short stroke. This hydraulic unit is arranged above or below the rolls, inside the so-called window of the rolling mill stand/housing. Of course, as already stated, one may use the hydraulic drive as a complete replacement for the electromechanical adjusting drive for the rolls. For this kind of retro-fitting particular constructions are known wherein the bore receiving the adjusting threaded sleeve which cooperates with the adjusting spindle, is closed through a cover, and the cylinder of the hydraulic drive is then placed inside of the housing window of the frame or stand. In other known construction the space is used that is now made available through the removal of the threaded adjusting sleeve and the hydraulic drive cylinder is inserted in that bore.
In some cases, the housing window is quite small so that the hydraulic drive can not be accommodated; in other cases the requisite the cylinder diameter of the hydraulic drive is larger than the now no longer used housing bore. In such a situation it is actually necessary to put these hydraulic drive above the frame. Here then, the piston rod will be run through the aforementioned bore and acts through a thrust bearing or the like on the rods. An example of this approach, for example disclosed in U.S. Pat. No. 4,007,618.
The latter construction is disadvantaged by the fact that the fastening of the cylinder of the hydraulic drive on the roll stand housing has to take up the maximum load that results from and during the rolling process. The state of the art proposes certain threaded connections and tension rods for purposes of fastening, but these modes of fastening the drive to the stand or housing are insufficient, at least the margin of safety is rather slim. Another disadvantage of the known approach is that the assembly as well as the disassembly in case of maintenance of the hydraulic drive is quite extensive and requires a large work area to accomplish that goal. Moreover, the aforementioned solution to the problem in accordance with the state art gives rise to the expectancy that owing to the expansion of frame parts that needed for fastening the hydraulic drive, on account of the rolling force, the quality of the rolled product deteriorates particularly because surface defects of various kinds appear on the rolled stock. Also, an exact measurement of the position of the rolls is no longer possible because the expansion of the aforementioned sleeve or other parts underload may introduce errors concerning the cylinder position in relation to the rolling stand and housing.